21066451 has 16 divisors (see below), whose sum is σ = 25643520. Its totient is φ = 16894080.

The previous prime is 21066449. The next prime is 21066457. The reversal of 21066451 is 15466012.

It is not a de Polignac number, because 21066451 - 2¹ = 21066449 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21066457) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 24690 + ... + 25528.

It is an arithmetic number, because the mean of its divisors is an integer number (1602720).

Almost surely, 2^21066451 is an apocalyptic number.

21066451 is a deficient number, since it is larger than the sum of its proper divisors (4577069).

21066451 is a wasteful number, since it uses less digits than its factorization.

21066451 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1074.

The product of its (nonzero) digits is 1440, while the sum is 25.

The square root of 21066451 is about 4589.8203668553. The cubic root of 21066451 is about 276.1831164219.

The spelling of 21066451 in words is "twenty-one million, sixty-six thousand, four hundred fifty-one".